An antigenic analysis of Dipetalonema viteae microfilariae and adult worms will be conducted. Soluble somatic and solubilized cuticular extracts and metabolic products of both parasitic stages will be prepared. These preparations will be fractionated by a combination of column chromatography, isoelectric focusing, isotachophoresis and polyacrylamide gel electrophoresis. Metabolic products will be isolated from culture media in which microfilariae and adult worms have been maintained in vitro. The various parasite antigens and their fractions will be used in immunologic studies on the humoral and cellular immune responses stimulated in hamsters by infection with D. viteae. Two resistance phenomena will be studied; the elimination of bloodstream microfilariae and the encapsulation and destruction of adult worms. Immunologically mediated glomerulonephritis induced by this parasite in hamsters will be studied by light and electron microscopy, along with other histopathologic manifestations of the disease.